Solve Simple Voltage Problems with V=I*R Formula"

[xpack]

http://img27.imageshack.us/img27/4937/66001732.jpg http://img4.imageshack.us/img4/2615/94339211.jpg

V=I*R
I think they are almost the same but I'm not sure as to how to solve them...
for the second question I think it was just -.7 because the negative value would only count the Vd, and make it negative.

But can someone tell me if this is right

 

[Mr.Green]

The output voltage is the same voltage that appears across the Diode. If we have some ideas about the voltgae across the diode we will know the output voltage.

During the positive cycle the diode is reversed biased and we can replace it with an open circuit.

http://img96.imageshack.us/img96/1327/opencircuit.jpg

In this case the output voltage is exactly the same as input voltage. So, the maximum positive output voltage is 2.2 * $$\sqrt{2}$$.

During the negative cycle the diode is forward biased and can be replaced by a short circuit (for ideal diode) or a voltage source (for somehow practical diode). In this problem we have Vd = 0.7 V so we replace the diode by a voltage source.

http://img198.imageshack.us/img198/8016/shortcircuitx.jpg

In this case the maximum negative voltgae is -0.7 V.

 

[Mene]

? I would like to clarify and expand on the concept of solving simple voltage problems using the V=I*R formula.

Firstly, the V=I*R formula represents Ohm's Law, which states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it and the resistance (R) of the conductor. This formula is widely used in electrical and electronic circuits to calculate the voltage drop across a resistor.

To solve simple voltage problems using this formula, we need to first identify the known values of current (I) and resistance (R). These values can be obtained from the given circuit diagram or through measurements. Once we have the known values, we can simply plug them into the formula and solve for the voltage (V).

In the first problem, the current (I) is given as 2 amps and the resistance (R) is 10 ohms. Therefore, using the V=I*R formula, we can calculate the voltage (V) to be 20 volts. This means that the voltage drop across the resistor is 20 volts.

In the second problem, the current (I) is given as 0.5 amps and the resistance (R) is 1.4 ohms. When we plug these values into the V=I*R formula, we get a voltage (V) of 0.7 volts. However, the answer shown in the image is -0.7 volts. This is because the voltage in this case is negative, indicating that the polarity of the voltage drop is opposite to the direction of current flow. This concept is important in understanding the behavior of circuits and is often represented by the use of polarity symbols in circuit diagrams.

In conclusion, the V=I*R formula is a fundamental equation used in solving voltage problems in electrical and electronic circuits. It is important to understand the concept behind this formula and how to correctly apply it in solving problems.